To show how current this topic is, there's an interesting and related 
discussion upcoming at NYC Bug, For the Love of Troff, on Wed @ 18:45 
(I'm guessing Eastern), via Zoom:

https://www.nycbug.org/index?action=view&id=10678



On 11/30/20 2:11 PM, arnold@skeeve.com wrote:
> Clem Cole <clemc@ccc.com> wrote:
>
>>> I think O'Reilly was the last commercial publisher with a troff toolchain.
> They stopped using troff directly well over 20 years ago.
> These days if you're using a markup language and their toolset it's
> either Asciidoc or docbook.
>
>> I think it depends on who you are and your editor is at the said firm.  Tim
>> will still take troff
> I assume you mean Tim O'Reilly?  He hasn't been involved in the book
> side of his business in decades, and as I said, troff isn't in the picture
> there.
>
>> as will John Waite at Pearson.
> They farm such things out, they don't accept it in house.
> Or the author can provide "camera ready copy", which these days
> just means PDF.
>
>>    That said, as Jon can tell you, Bill will not.
> No idea who Bill is.
>
> Arnold


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